The following position chills to -1/2 (1/2 point for White).
If Black plays the result is 0. That chills to -1, because it costs Black a point to make a play.
reverses. The result is -1, which chills to 0.
The chilled game looks like this:
{ -1 | 0 }
In CGT that equals -1/2. That's no surprise. Go players already knew to count that as 1/2 point of White territory.